Biochanin A improves fibre fermentation by cellulolytic bacteria

Aims

The objective was to determine the effect of the isoflavone biochanin A (BCA) on rumen cellulolytic bacteria and consequent fermentative activity.

Methods and Results

When bovine microbial rumen cell suspensions (n = 3) were incubated (24 h, 39°C) with ground hay, cellulolytic bacteria proliferated, short‐chain fatty acids were produced and pH declined. BCA (30 μg ml^?1) had no effect on the number of cellulolytic bacteria or pH, but increased acetate, propionate and total SCFA production. Addition of BCA improved total digestibility when cell suspensions (n = 3) were incubated (48 h, 39°C) with ground hay, Avicel, or filter paper. Fibrobacter succinogenes S85, Ruminococcus flavefaciens 8 and Ruminococcus albus 8 were directly inhibited by BCA. Synergistic antimicrobial activity was observed with BCA and heat killed cultures of cellulolytic bacteria, but the effects were species dependent.

Conclusions

These results indicate that BCA improves fibre degradation by influencing cellulolytic bacteria competition and guild composition.

Significance and Impact of the Study

BCA could serve as a feed additive to improve cellulosis when cattle are consuming high‐fibre diets. Future research is needed to evaluate the effect of BCA on fibre degradation and utilization in vivo.     

Has photosynthetic capacity increased with 80 years of soybean breeding? An examination of historical soybean cultivars

Crop biomass production is a function of the efficiencies with which sunlight can be intercepted by the canopy and then converted into biomass. Conversion efficiency has been identified as a target for improvement to enhance crop biomass and yield. Greater conversion efficiency in modern soybean [Glycine max (L.) Merr.] cultivars was documented in recent field trials, and this study explored the physiological basis for this observation. In replicated field trials conducted over three successive years, diurnal leaf gas exchange and photosynthetic CO₂ response curves were measured in 24 soybean cultivars with year of release dates (YOR) from 1923 to 2007. Maximum photosynthetic capacity, mesophyll conductance and nighttime respiration have not changed consistently with cultivar release date. However, daily carbon gain was periodically greater in more recently released cultivars compared with older cultivars. Our analysis suggests that this difference in daily carbon gain primarily occurred when stomatal conductance and soil water content were high. There was also evidence for greater chlorophyll content and greater sink capacity late in the growing season in more recently released soybean varieties. Better understanding of the mechanisms that have improved conversion efficiency in the past may help identify new, promising targets for the future.     

The microbiome impacts host hybridization and speciation

Microbial symbiosis and speciation profoundly shape the composition of life’s biodiversity. Despite the enormous contributions of these two fields to the foundations of modern biology, there is a vast and exciting frontier ahead for research, literature, and conferences to address the neglected prospects of merging their study. Here, we survey and synthesize exemplar cases of how endosymbionts and microbial communities affect animal hybridization and vice versa. We conclude that though the number of case studies remain nascent, the wide-ranging types of animals, microbes, and isolation barriers impacted by hybridization will likely prove general and a major new phase of study that includes the microbiome as part of the functional whole contributing to reproductive isolation. Though microorganisms were proposed to impact animal speciation a century ago, the weight of the evidence supporting this view has now reached a tipping point.     

Predation of <Emphasis Type="Italic">Halyomorpha halys</Emphasis> (Hemiptera: Pentatomidae) from Web-Building Spiders Associated with Anthropogenic Dwellings

The brown marmorated stink bug, or Halyomorpha halys, is an invasive pest in North America and Europe that causes severe agricultural damage and nuisance problems for homeowners; and it is originally from China, Taiwan, and the Republic of Korea. While the natural enemy community of H. halys has been evaluated in several agroecosystems, it has not been examined where H. halys overwinters in anthropogenic structures. The aims of the current study were to evaluate 1) whether spider webs commonly found in the home and yard can successfully ensnare H. halys, 2) whether entanglement resulted in consumption by spiders inhabiting the webs, and 3) how frequently H. halys becomes entangled in webs under ambient conditions. To accomplish this, adult H. halys were introduced into webs in and near anthropogenic structures in West Virginia and Maryland, United States, and the behavior of spiders was observed for 5-min intervals at 0, 1, 2, and 24 h after introduction. In addition, a survey of webs was performed to determine the frequency with which spiders naturally capture H. halys inside buildings and in the landscape. Overall, the study found seven spider families in anthropogenic structures. Adult H. halys that were introduced into the webs of Theridiidae, Pholcidae, or Agelenidae had a greater than 50% chance of being ensnared and consumed. Adult H. halys were found naturally most often in webs of Theridiidae. Webs with a funnel or cob web architecture had the greatest probability of ensnaring H. halys, while those with orb structures resulted in the fewest caught. In the wild, 13–20% of spider webs contained dead H. halys. Our results suggest that spiders may be an important contributing factor for mortality of H. halys at overwintering sites, and spiders in or outside homes may help reduce nuisance problems caused by H. halys.     

Exploring the linkage between cell culture process parameters and downstream processing utilizing a plackett‐burman design for a model monoclonal antibody

Linkage of upstream cell culture with downstream processing and purification is an aspect of Quality by Design crucial for efficient and consistent production of high quality biopharmaceutical proteins. In a previous Plackett‐Burman screening study of parallel bioreactor cultures we evaluated main effects of 11 process variables, such as agitation, sparge rate, feeding regimens, dissolved oxygen set point, inoculation density, supplement addition, temperature, and pH shifts. In this follow‐up study, we observed linkages between cell culture process parameters and downstream capture chromatography performance and subsequent antibody attributes. In depth analysis of the capture chromatography purification of harvested cell culture fluid yielded significant effects of upstream process parameters on host cell protein abundance and behavior. A variety of methods were used to characterize the antibody both after purification and buffer formulation. This analysis provided insight in to the significant impacts of upstream process parameters on aggregate formation, impurities, and protein structure. This report highlights the utility of linkage studies in identifying how changes in upstream parameters can impact downstream critical quality attributes. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:163–170, 2017     

Prolonged apoptosis in mitochondria-rich cells of tilapia (<Emphasis Type="Italic">Oreochromis mossambicus</Emphasis>) exposed to elevated salinity

The time-course of programmed cell death (apoptosis) during reorganization of gill epithelium in salinity-stressed tilapia was analyzed using a recently developed method based on laser scanning cytometry (LSC) of dissociated gill cells. Apoptosis in mitochondria-rich cells (MRC) was distinguished from that in other cell types using Na⁺/K⁺ ATPase (NKA) as a cell-specific marker. Caspase 3/7 activity in MRC, assessed using LSC and microplate assays, increased significantly starting at 6 h of salinity stress and remained elevated for at least 5 days. This time-course of apoptosis in MRC during acute salinity stress was reflected in elevated apoptotic DNA fragmentation. In parallel to induction of apoptosis, MRC showed a pronounced shift to G2 phase of the cell cycle, which is indicative of G2/M cell cycle arrest, and an increase in NKA abundance per MRC. Unlike in MRC, apoptosis was not significantly increased in other gill cell types, although there was a small transient increase in DNA fragmentation at 6 h. G2 arrest was also observed. Overall, we interpret our data as evidence for a significant role of apoptosis in the extensive reorganization of MRC populations that takes place during salinity acclimation, perhaps similar to its well-established role during organismal development.